Interest computing machine



March 27, 1934. BARTHQLOMEW 1,952,303

INTEREST COMPUTING MACHINE Filed Oct. 7, 1931 3 Sheets-Sheet 1 1 I Hm I:

I I3 MI I L I I HHHmlT /fiin;I??? 2? I |||.1 l W n 13 10 13 7 9 INVENTOR zgxw March 1934- M. M. BARTHOLOMEW ,95

INTEREST COMPUTING MACHINE Filed 001:. 7. 1931 3 Sheets-Sheet 2 1v W m l u. 54. if g9 E INVENTOR Tp v March 27, 1934. M. M. BARTHOLOMEW INTEREST COMPUTING MACHINE Filed Oct. 7, 1931 3 Sheets-Sheet 3 km N mm \N WMMM 5 m M Y T N E V N 1 a .A m Y B i M w m m w E w M H 4- l I I I! 9 w MN w g Q t mm H w ww by m m LE- T Patented Mar. 27, 1934 UNITED STATES PATENT OFFHIE Application October 7,

12 Claims.

This invention relates to interest computing machines by means of which the amount of interest may be computed on any desired principal and at any desired rate of interest over any desired elapsed time period, and has for. its primary object to provide an improved combination and arrangement of principal-counting, elapsed time-measuring, interest rate-changing, and interest-registering devices. A further object of to my invention is to provide a mechanism of simple economical construction which may be readily operated by hand to produce the desired computation in a purely mechanical manner. For this purpose, my invention contemplates an elapsed time period gear set comprising a series of coaxially mounted gears having graded numbers of teeth representing respectively different time periods for which any desired rate of interest may be computed; a principal-counting mechanism arranged to be driven in correlation with the elapsed time gear assembly for measuring the desired principal for which the interest is to be computed; an interest rate-changing gear assembly comprising a series of coaxially mounted gears having graded numbers of teeth representing respectively different desired rates of interest at which the interest is to be computed; and an interest-counting mechanism adapted to be operated in correlation with the above-mentioned mechanisms for registering the amount of the desired interest to be computed.'

More specific objects of invention will appear in the specification and be pointed out on the drawings in connection with certain features of construction recited in the claims.

The drawings show a preferred embodiment of my invention adapted for the computation of interest connected with various transactions in banking and related spheres of activity. In the drawings,

Figure 1 is a front elevation of a preferred embodiment of my improved interest calculating machine.

Figure 2 is a top plan view of the same.

Figure 3 is an enlarged transverse section of the interest-measuring mechanism.

Figure 4 is an enlarged vertical section correspending to the line 4-4 of Figure 1.

Figure 5 is a fragmentary horizontal section on the line 5-5 of Figure 3.

Figure 6 is a schematic top plan View of the gearing trains with the several mechanisms arranged for calculating interest at the rate of 5% over an elapsed time period of 100 days.

1931, Serial No. 567,409

Figure '7 is a schematic front elevation of the same.

Figure 8 is a schematic front elevation of the gears similar to that shown in Figure '7 with the several mechanisms arranged for calculating interest at the rate of 6% for an elapsed time period or" 30 days.

Referring more particularly to the drawings, a base plate 1 is provided for mounting the several mechanisms in suitable arrangement with respect to each other for permitting the desired adjustments and connections for carrying out any desired interest computation. Journalled at one end in a front supporting plate or bracket 2 and at its rear end in a bracket arm 3 is a rotary shaft 1 to which are keyed a series of elapsed time period measuring gears 5, said gears, in the present embodiment of my invention, being provided with teeth graded in numbers from 16 to 100 for permitting computation of interest over time periods ranging from 10 days to 100 days. Presented forwardly from the front plate 2 is a boss 6 which carries a stud '7 upon which is journalled a gear 8 provided with a rigidly connected crank arm 9. The gear 8 meshes into a pin on 10 of a compound gear which includes said pinion and a larger gear 11, said compound gear being journalled upon a stud 12 which is presented forwardly from the front plate 2. The larger gear 11 of said compound gear meshes into a spur pinion 13 which is keyed to the for ward end of the time-measuring spindle 4. For convenience, a finger grip 14: may be mounted on the forward end of the spindle 4 for adjusting the positions of: the counters hereinafter to be referred to. A principal-counting and registering device 15 is preferably permanently geared to a particular one of the graded gears 5 of the time period measuring gear cone as shown in Figures l, 6, 7 and 8. As shown in Figure 6, the Gil-tooth gear 5a has been selected as a convenient gear for this purpose, said gear being permanently in mesh with an idler gear 16 which turn drives two other idler gears 17 and 18, said idler gear 18 being arranged to mesh with a spur pinion 19 keyed to one end of a spindle 29 which is the primar driving spindle of the principal-counting mechanism. Also keyed to the spindle 20 is a r latively broad faced spur gear 21 which as shown in Figure 6 meshes with lower spur gear 22 which is mounted upon a spindle 23. Keyed to the spindle 23 in the rear of ear 22, is a spur pinion 24 which meshes into a spur gear 25 carried by a spindle 26. A spur pinion 2'? which is also keyed to the spindle 26 groove 56 in the under surface 0 meshes into a lower spur gear 23 to a dle 29. A spur pinion 36 wh ch is also keyed to the spindle 29 meshes with an upper spur gear 31 carried by a spindle 32, a spur pinion 33 being keyed to the spindle in the rear oi spur gear 31 and meshing into a lower 34 keyed to a spindle 35. Keyed to s' 35 in the rear of gear as, is pinion 36 which meshes into an upper ried by a spindle 33. The spindles 32, and 38, above referred to, may constitute the indicator shafts which register the amount of the principal for which the interest comp ation is being made, said spindles being (11 n through a chain or gears provided with teeth of suitable numbers for correlating the amounts reg with the other operations of the machine.

Referring now to Figure 2, a pair of parallel guide bars 39 may be rigidly secured to upper surface or the base-plate i to provide clined guideways for the longitud" Extending longitudinally of the ba parallel to the guide bars 39 is a sp as shown in Figure 3 operates iii in the under surface of the s id, 41 as well as the guides 39 lel to the slant of the nearer ed cone 5. The longitudinal adjusti- 40 is designed to permit a time L ment of the interest computing mesh" in any desired limits for which the been designed. As shown Fi ures 3 and slide 40 may be yieldably retai ed ijusted position by means of a 43 which is pressed by a spring i t ment with a serrated rack-bar i5 ioriner 1. inner wall of the left-hand slotted guide rack-bar being adapted to slide over as the slide is moved longitudinally of plate 1. As shown in Figures 1 and i, a 46 limits the extreme forward nositi slide 40. As shown best 4G is provided with paral between which is slida slide 18 which isthus adapted to be moved towards and away from the gear cone 5. A dog 49 which is movable in one o r des under the pressure of a spring 50 ably interlock with a serrate the adjacent edge of the slide l ed to retain said slide in adjustc fixed stop 52 which projects up left-hand lateral edge of slide movement of the slide 48 away cone 5. Referring now to F-5dseen that the slide 48 carries late-i slotted guides 53 between which a second 131 tudinal slide 54 is reciorocably mounted on a spur gear 3'? can In v slide 53 being constrained to an cbli ue means of a spline 55 embedded in u; face of slide 43 and projecting The resulting oblique movement or is in a direction parallel. to the slant U1 nearer edge of an interest rate-cl1anging gear cone to be presently referred to. of this slide 54 is under the yieldable of a dog 57 pressed by a 53 into in the left-hand slotted guide bar ring now to Figure 4, the secondsurface or" slide 54. Any adjusted position of this s cond transverse slide 61 may be yieldably mainp upon a rack-bar 63 in the adjacent edge of the second transverse slide 61. Mounted upon the upper transverse slide 61 is the interestcounting and registering mechanism which is designated by the general refrence character 64. Said interest-counting and registering mechanism substantially similar in construction to the principal-counting and registering mechanism and is driven by the elapsed time period gear cone through the "iterest rate-changing mechanism now to be described. As shown in i igures 1 and 2 of the drawings, the transverse slide l0 carries two axially spaced bearing plates 65 and 66. Within said bearing plates is journalled a jack shaft 67 which carries an idler gear 68, said idler gear being arranged to mesh with a spur gear 59 which is keyed to a shaft '70 upon which are coaxially mounted a series of interest rate-changing spur gears which are graded by the niunbers of teeth with which they are provided to correspond with various interest rates at which interest is to be computed on a given principal. be understood from the description given above the several slides arranged to the left or elapsed time period cone gears 5, that the int mediate idler gear 68 may be adjusted longitudmally of the cone gear 5 and moved 1ateraliy into mesh with any gear on said gear cone fo the purpose of connecting the interest rateanging gear cone with any gear 5 representing a given elapsed time period. Referring now to Figure '7, the interest-registering mechanism is provided with an intermediate idler gear 72 hich may be moved into or out of mesh with any particular gear 71 in the interest rate gear cone. adjustment is provided for by the movement of the uppermost slide 61 (see Figure 4) which carries the interest-registering mechanism; As shown in Figures 4, 6 and 7, the chain of gears for registering the amount of interest, comprises a series of compound gears driven by a pinion '73 which receives its power' from the idler gear 72. The gear train referred to comprises driving pinion 73, lower spur gear '74, lower spur pinion '75, upper spur gear 76, upper spur pinion 77, lower spur gear '78, lower spur pinion '29, upper spur gear 80, upper spur pi on 81, lower spur gear 82, lower spur pinion and u per spur gear 84-. carry driving pinion 73, upper spur pinion 77, upper spur pinion 81, and upper spur gear 64, constitute the number spindles of the counting mechanism. Said spindles are respectively designated by the reference characters 85, 86, 87 and 88 (see Figure 3). While the counting indicators may, if desired, be mounted directly upon the spindles 85, 86, 87 and 88, I prefer to provide counting The spindles which indicated in Figure 1, I prefer to provide this openings 89 through which the register- L the interest-counting mechanism. As shown in Figure 3, the driving spur pinion '73 meshes into an idler gear 89 which is interposed between the driving pinion and a spur pinion 90, on an upper counting spindle 91. Said spindle 91 carries a registering disk 92 which is suitably graduated to indicate the number of cents in the amount of interest to be registered. Mounted upon spindle 85 is a disk 93 which carries a radial tooth 94, said radial tooth being adapted to mesh with alternate teeth 95 of a gear carried by a second upper spindle 96 upon which is mounted a second registering disk 97, the gear ratios being suitably designed to rotate the disk 97 once for every ten rotations of the counting disk 92. In a similar manner, a third registering disk 98 is rotated once for every ten rotations of the disk 97; a fourth registering di .4 99 is rotated once for every ten rotations of the disk 98; and a fifth registering disk 100 is rotated once for every ten rotations of the disk 99. This particular embodiment of the counting mecha nism is therefore adapted to indicate from right to left, cents, dollars, tens of dollars, hundreds of dollars, and thousands of dollars. The incicated amounts, of course, may be indefinitely 6' panded by the addition of registering disks or by the shifting of the decimal point in a given result. The method of using my improved interest-computing machine will now be understood and may be briefly explained as foll Assuming, for example, that interest is to be computed on $575.00 at 5% for 100 days, the operator imparts a longitudinal movement to the bottom slide 40 to bring the intermediate idler gear 68 (see Figure 2) into transverse alinement with the 100-tooth gear at the extreme "front end of the elapsed time cone gear 5. For this purpose, an indicating finger 101 which is mounted on the left forward corner of the slide 40, is movable along a scale 102 on the upper surface of guide bar 39. This adjustment having been accomplished, the lower transverse slide i8 is moved toward the gear cone 5, until the idler gear 68 is enmeshed with the 100-tooth cone gear 5. This step having been accomplished, the upper longitudinally movable slide 54 is next adjusted to bring the idler gear 72 opposite to the particular gear '71 in the interest rate-changing gear cone which represents 5%. This rate of interest is indicated by a scale 103 formed on the upper surface of the lower transverse slide 48 by means of an indicator finger 104 carried by the slide 54. The upper transverse slide 61 which carries the interest-registering mechanism, is then moved toward the interest rate-changing cone gear 71 to bring the interposed idler gear '72 into mesh with the particular gear 71 which represents a rate of 5% interest. With these adjustments made, the crank arm 9 is then rotated until the amount $575.00 is indicated on the registering disks of the principal item registering mechanism 10. Thereupon, the interest-registering disks on the interest-computing mechanism 64 will indicate the desired amount of interest on $575.00 for 100 days at 5%. As shown diagrammatically in Figure 8, the relative arrangement of the gears is shown diagrammatically for a similar computation of interest on $575.00 at 6% for 30 days. For this purpose, the interposed idler gear 68 is arranged to mesh with the 30-tooth gear on the cone gear 5 while the interposed idler gear '72 is arranged to mesh with the gear having 24 teeth on the interest rate changing gear cone '71, the numbers of teeth in and permanently geared to said elapsed timeear cone, a main slide reciprocable over an inclined path substantially parallel to the slant of said elapsed time gear cone, a lower transverse slide reciprocable on said main slide towards and away from said elapsed time gear cone, an interest-rate gear cone mounted on said transverse slide and movable thereby into and out of geared connection with any particular one of the gears in the elapsed time gear cone, a longitudinal slide movable obliquely on said lower transverse slide over a path substantially parallel to the slant of the interest-rate gear cone, an upper transverse slide movable towards and away from said interest-rate gear cone, and an interestcounter mounted on the upper transverse slide and movable into and out of geared connection with any particular gear of the interest-rate gear cone.

2. In an interest computing machine, the combination of an elapsed time gear assembly comprising a series of coaXially-arranged graded gears, principal-counting mechanism geared to said gear assembly, an assembly of coaxially arranged graded interest-rate gears, interest-registering mechanism, means for connecting said interest-rate gears to any gear in said elapsed time gear assembly and means for connecting said interest registering mechanism to any gear in said interest-rate gear assembly.

3. In an interest computing machine, the combination of an elapsed time gear assembly comprising a series of coaxially-arranged graded gears rotatable in unison, principal-counting mechanism geared to said gear assembly, an assembly of graded interest-rate gears movable longitudinally and transversely with respect to said elapsed time assembly for connecting said interest-rate assembly with any one of said elapsed time graded gears, and an interest-registering mechanism movable longitudinally with respect to and transversely into and out of geared connection with any particular one of the graded series of gears of said interest-rate gear assembly.

a. In an interest computing machine, the combination of an elapsed time gear assembly comprising a series of coaxially-arranged graded gears rotatable together about a fixed axis, principal-counting mechanism geared to said series of graded gears, a slide movable longitudinally and transversely with respect to said eiapsed time gear assembly, an assembly of graded interest-rate gears rotatable together about an axis and carried by said slide for connecting said interest-rate assembly with any one of said time gears, and an interestregistering mechanism movable longitudinally and transversely with respect to said interestrate gear assembly and into and out of geared connection with any desired gear of said interestrate gear assembly.

5. In an interest computing machine, the combination with a principal-counter, of an elapsed time gear cone, means for rotating said elapsed time gear cone and principal-counter, a slide movable over a path extending substantially parallel to the slant of the adjacent side of said gear cone, a second slide movable on the firstl mentioned slide over a path extending substantially transversely with respect to the axis or" said gear cone, an interest-rate geai" cone mounted on the second-mentioned slide, a third slide movable on said second-mentioned slide over a path extendin substantially parallel to the axis of interest-rate gear cone, a fourth slide movable on the third slide in a direction substantially transverse to the axis of said interestrate gear cone, and an interest-counter mounted on said fourth slide for connecting said interestcounter to any particular gear in said interestrate gear cone.

6. In an interest computing machine, the combination of a main base-plate,an elapsed time cone gear assembly mounted on said base-plate to rotate about fixed axis, a principal-counter,

means for rotating said elapsed time cone gear and driving said principal-counter in unison th rewith, a slide movable on said base-plate over an inclined path substantially parallel to the adjacent 'dge of aid elapsed time cone gear, a second s movable on the first-mentioned slide towards and away from said elapsed time gear cone, an interest-rate gear cone rotatably mounted on said second slide, a connection gear rotatable with interest-rate gear cone and movable by second slide into and out of geared connection with any the gears in said elapsed time gear cone, a third slide obliquely movable on the second slide along the slant of the nearer side of the interest-rate gear cone, a fourth slide movable on the third slide transversely to the a is or" said interest-rate cone gear, and interest-counter mounted on the lastmentioned slide and movable into and out of position to geared to any particular gear in the interes ate gear cone.

2. In an interest computing machine, the com- .,tion or" main haze-plate, an elapsed time gear :nbly rho on common axis on said hate-plate, said sed time gear assembly comling a shaft 1 tata is on a fixed a series f gears coaxially arranged on said shaft, a ch n of is mounted on said base-plate for n3 said shaft, principal-counting mechanism lllO'd ,d on said base-plate and permanently geared to said shaft, a main slide reciprocable over an inclined path substantially parallel to a plane to the adjacent edges of said series of a transverse slide reciprocaole said main towards and away from said series of graded gears, graded change on said transverse slide movable into and d connection with any of the gears d ti 3e assembly, a longitudinal eiy reciprocable on said transverse lsverse slide movable towards away fron said tme gear assembly, and an interest-con mes. ted the last-mentioned transverse slide and movable into out of connection ith said graded change gears on the transverse slide.

8. In an machine, the combination of pat-counting niecha cone constructed and art ariah y connected to said nting mechanism,

ng mechanism to cone, and an interest counter movable into and out of geared connection with any particular gear of the interest-rate gear cone.

9. In an interest computing machine, the combination of a main base-plate, an elapsed time gear cone mounted on said base-plate, principalcounting mechanism mounted on said base-plate and geared to said elapsed time gear cone, a slide reciprocable on said base-plate longitudinally of said elapsed time gear cone, an interest-rate gear cone movable on said slide and into and out of geared connection with any particular one of the in the elapsed time gear cone, and an interest-counter slidably connected to said slide and movable into and out of geared connection with any particular gear of the interest-rate gear cone.

10. In an interest computing machine, the combination of a main base-plate, elapsed time and principal-counting mechanism mounted on said base-plate and rotatable in unison, an interest-rate gear cone movably mounted on said baseplate, connection rotatable with said incone, means for connecting said at." in variably geared relations to and principal-counting mechnterest-counter movable longitr tcrest gear cone and into and out oi position to be geared to any particular gear the interest-rate gear cone.

ll. In an interest computing machine, the combination of a main base-plate, an elapsed time cone gear assembly mounted on said baseplate to rotate about a fixed a principalcountor, for rotating said elapsed time cone and driving said principal-counter in therewith, a slide movable on said baseplate adjacent to said elapsed time cone gear, a s ide movable on the first-mentioned slide towards and away from said elapsed time gear cone, an irerest-rate gear cone rotatably mounted on sosecond a connection gear rotatable with said interest-rate gear cone and movable by said second slide into and out of geared connection with any of the gears in said elapsed time gear cone, 2, third slide movable on the second slide along the interest-rate gear cone,

fourth slide movable on the third slide transversely to the axis of said ll terest-rate cone gear, and an interest-counter mounted on the lastmeniioned slide and movable into and out 01' position to be geared to any particular gear in the interest-rate gear cone.

12. In int rest computing machine, the combination of an elapsed time gear assembly mounted on a common rotary axis, principalcounting mechanism rotatable with elapsed time gear assembly, main slide reciprocable past the adjacent edges of th gears in said gear assem 1y, a transverse slide rcciprocable on said main slide towards and away from. said gear assembly, graded change gears on said transverse slide movable and out of geared connection with any or" the g ars in the elapsed time "ear assembly, a longitudinal slide reciprocable on said transverse slide, a second transverse slide 31 said change gears.

IVIILES M. BARTHOLOMEW.

"o and out of geared connection with any of 

